Re: DOF preview in OVFs of DSLRs is crippled

Discussion in 'Digital Photography' started by Ilya Zakharevich, Jun 17, 2008.

  1. [A complimentary Cc of this posting was sent to
    Alfred Molon
    <>], who wrote in article <>:
    > http://www.dphotoexpert.com/2007/09/21/live-view-versus-the-cheating-
    > dslr-viewfinder/
    >
    > See the two images of the chessboard. Apparently because of the
    > compromises in the OVFs of DSLRs you see more DOF than you really get.
    >
    > According to the article the only way to get an accurate DOF preview is
    > through a direct video feed from the main sensor to the LCD display.


    Apparently, the author has no clue that one should match the
    "effective f-number" of the focussing screen to the wide-open-f-number
    of the lens.

    The default focussing screen are optimized for kit-like lenses with
    very small wide-open aperture. *Of course* they do not catch light
    from the outside areas of the lens, so give a wrong impression about
    DOF. A matched screen should perform MUCH better.

    But if one forgets this piece of illiteracy, the conclusion of the
    paper holds...

    Yours,
    Ilya
     
    Ilya Zakharevich, Jun 17, 2008
    #1
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  2. Alfred Molon wrote:
    > In article <g38vef$25lq$>, Ilya Zakharevich
    > says...
    >
    >> But if one forgets this piece of illiteracy, the conclusion of the
    >> paper holds...

    >
    > And that is the problem. I'm about to switch to a DSLR (from the Sony
    > R1) and the more I learn about DLSRs, the less impressed I am.
    > Problems with DLSRs include:
    >
    > 1. Front focus/back focus issues: this problem simply does not exist
    > in a camera with contrast AF
    > 2. Mirror slap vibrations: you are forced to use MLU which not all
    > DSLRs offer. Problem does not exist in compacts...
    > 3. DLSR Viewfinder which could be misaligned with the main sensor
    > resulting in tilted images. Problem does not exist in compacts.
    > 4. Optical viewfinder not showing 100% of the scene (this is really
    > pathetic - any camera with live preview shows 100%)
    > 5. Optical viewfinder being too dark if you use DOF preview
    > 6. DOF preview being inaccurate anyway for checking DOF
    >
    > The only solution to all these problems is to have live preview on a
    > high res LCD screen or EVF.


    Alfred,

    Whilst you are theoretically correct about these issues, in practice:

    1 - contrast AF is desperately slower than phase-detect AF.

    2 - not an issue for 99% of my photos.

    3, 4 - are you sure that all compacts, and live-view cameras, give exactly
    100% framing, and don't allow some margin?

    5 - Perhaps, but it depends on just what is "too dark" in particular
    circumstances.

    6 - That's a function of a particular viewfinder design, not a generic
    defect.

    LCD screens can be very poor in daylight, and require that you focus your
    eyes closely, and/or hold the camera in a poor position.

    EVFs - at their present resolution - are a very poor substitute for an
    optical viewfinder. They can have an advantage in low-light level
    conditions where the gain-up feature allows a brighter display than direct
    view, but ii is suitable for framing only, not for any critical
    judgements.

    As you will know, I have used both types.

    Cheers,
    David
     
    David J Taylor, Jun 18, 2008
    #2
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  3. Ilya Zakharevich

    Cynicor Guest

    Alfred Molon wrote:
    > In article <g38vef$25lq$>, Ilya Zakharevich says...
    >
    >> But if one forgets this piece of illiteracy, the conclusion of the
    >> paper holds...

    >
    > And that is the problem. I'm about to switch to a DSLR (from the Sony
    > R1) and the more I learn about DLSRs, the less impressed I am. Problems
    > with DLSRs include:
    >
    > 1. Front focus/back focus issues: this problem simply does not exist in
    > a camera with contrast AF
    > 2. Mirror slap vibrations: you are forced to use MLU which not all DSLRs
    > offer. Problem does not exist in compacts...
    > 3. DLSR Viewfinder which could be misaligned with the main sensor
    > resulting in tilted images. Problem does not exist in compacts.
    > 4. Optical viewfinder not showing 100% of the scene (this is really
    > pathetic - any camera with live preview shows 100%)
    > 5. Optical viewfinder being too dark if you use DOF preview
    > 6. DOF preview being inaccurate anyway for checking DOF
    >
    > The only solution to all these problems is to have live preview on a
    > high res LCD screen or EVF.


    Conclusion: Cell phone cameras outclass the Nikon D3.
     
    Cynicor, Jun 18, 2008
    #3
  4. Ilya Zakharevich

    Ray Fischer Guest

    Alfred Molon <> wrote:
    >In article <g38vef$25lq$>, Ilya Zakharevich says...
    >
    >> But if one forgets this piece of illiteracy, the conclusion of the
    >> paper holds...

    >
    >And that is the problem. I'm about to switch to a DSLR (from the Sony
    >R1) and the more I learn about DLSRs, the less impressed I am.


    When you worship technology you will be disappointed.

    > Problems
    >with DLSRs include:
    >
    >1. Front focus/back focus issues: this problem simply does not exist in
    >a camera with contrast AF


    How fast can a P&S focus? A DSLR takes maybe 1/5th of a second.

    >2. Mirror slap vibrations: you are forced to use MLU which not all DSLRs
    >offer. Problem does not exist in compacts...


    It doesn't exist in SLRs, either.

    >3. DLSR Viewfinder which could be misaligned with the main sensor
    >resulting in tilted images. Problem does not exist in compacts.


    Vastly higher resolution in the SLR's viewfinder.

    >4. Optical viewfinder not showing 100% of the scene (this is really
    >pathetic - any camera with live preview shows 100%)


    NO camera with live preview shows 100% of the scene. They all show
    very low resolution versions of the scene.

    >5. Optical viewfinder being too dark if you use DOF preview


    LCD screen completely unviewable in bright light.

    >6. DOF preview being inaccurate anyway for checking DOF


    That one is completely false.

    >The only solution to all these problems is to have live preview on a
    >high res LCD screen or EVF.


    When you find a camera that has a 6MP LCD screeen you let us know.

    --
    Ray Fischer
     
    Ray Fischer, Jun 18, 2008
    #4
  5. Ilya Zakharevich

    nospam Guest

    In article <>, Alfred
    Molon <> wrote:

    > In article <48593a81$0$17227$>, Ray Fischer
    > says...
    >
    > > >2. Mirror slap vibrations: you are forced to use MLU which not all DSLRs
    > > >offer. Problem does not exist in compacts...

    > >
    > > It doesn't exist in SLRs, either.

    >
    > Then why do some DSLRs have MLU? Besides I saw some sample images,
    > with/without MLU where you could clearly see that the image taken
    > without MLU was soft.


    it helps in some cases at some shutter speeds. it's not required in
    all situations.

    > > >4. Optical viewfinder not showing 100% of the scene (this is really
    > > >pathetic - any camera with live preview shows 100%)

    > >
    > > NO camera with live preview shows 100% of the scene. They all show
    > > very low resolution versions of the scene.

    >
    > They do. 100% means that they show the whole scene being captured,
    > without cutting away the borders.


    no, they don't. two that came up in a quick google search:

    97% coverage:
    <http://www.steves-digicams.com/nikon880.html>

    80% coverage:
    <http://www.dpreview.com/news/0702/07022006_nikonp5000.asp>

    > > >5. Optical viewfinder being too dark if you use DOF preview

    > >
    > > LCD screen completely unviewable in bright light.

    >
    > Then use the EVF.


    evf or lcd can be too slow for fast action photography. they also have
    issues in low light.

    > > >6. DOF preview being inaccurate anyway for checking DOF

    > >
    > > That one is completely false.

    >
    > Completely true. See the link I posted:
    > http://www.dphotoexpert.com/2007/09/21/live-view-versus-the-cheating-
    > dslr-viewfinder/


    it depends on the viewfinder screen. if dof accuracy is important,
    select a different screen.

    > Actually, forgot to mention in my previous post that it's a shame that
    > DLSRs have no movie mode. But I guess it's just a matter of time until
    > DSLRs catch upo here, because most new DSLRs have a live view capable
    > sensor.


    it's coming. pentax has a 20fps mode in the k20d. adding video is
    really nothing more than firmware.
     
    nospam, Jun 18, 2008
    #5
  6. Alfred Molon <> wrote:
    >And that is the problem. I'm about to switch to a DSLR (from the Sony
    >R1) and the more I learn about DLSRs, the less impressed I am. Problems
    >with DLSRs include:
    >
    >1. Front focus/back focus issues:
    >2. Mirror slap vibrations:
    >3. DLSR Viewfinder which could be misaligned with the main sensor
    >4. Optical viewfinder not showing 100% of the scene (this is really
    >5. Optical viewfinder being too dark if you use DOF preview
    >6. DOF preview being inaccurate anyway for checking DOF
    >
    >The only solution to all these problems is to have live preview on a
    >high res LCD screen or EVF.


    Actually, considering how bad SLRs are, I would very strongly suggest
    you stick with your Sony R1. Obviously it doesn't have all those
    problems and is a much better match for you.

    jue
     
    Jürgen Exner, Jun 18, 2008
    #6
  7. Alfred Molon <> wrote:
    >In article <>, Jürgen Exner
    >says...
    >
    >> Actually, considering how bad SLRs are, I would very strongly suggest
    >> you stick with your Sony R1. Obviously it doesn't have all those
    >> problems and is a much better match for you.

    >
    >But I want more MP ;-)


    Would 39 MPix be sufficient:
    http://www.hasselbladusa.com/promotions/h3dii.aspx

    jue
     
    Jürgen Exner, Jun 18, 2008
    #7
  8. Ilya Zakharevich

    Matt Ion Guest

    TRoss wrote:

    >>>> 5. Optical viewfinder being too dark if you use DOF preview
    >>> LCD screen completely unviewable in bright light.

    >> Then use the EVF.

    >
    > Repeat after me ... DSLRs do not have an EVF.
    >
    > If the camera has an EVF, it isn't a DSLR. A camera that has an EVF
    > has no need for a reflex mirror, which is one defining characteristic
    > of an SLR camera. The other defining characteristic is a single lens.


    Tell that to my 40D. You saying it isn't an SLR because it actually has
    an EVF live-view function? It still has a reflex mirror... and a
    mechanical shutter... and a single lens.

    > Besides, an EVF would pretty much be worthless for checking DOF. The
    > size is too small and the resolution is too low.


    The 40D's live view has a zoom feature, up to (if memory serves) 10X
    magnification... basically just displaying a crop from the sensor.
    Works great for manual focusing when shooting macro. You don't need to
    see the whole image, just a select area of it.

    > Also, consider the lifespan of a mechanical shutter is around 100,000
    > actuations. At 24fps, you would get about 1 hour of movie footage
    > before shutters start to fail.


    Do film movie cameras not use mechanical shutters? My old Super-8 cam
    did... never had to change the shutter in several hundred hours of usage.
     
    Matt Ion, Jun 18, 2008
    #8
  9. Alfred Molon <> wrote:
    > In article <>, J?rgen Exner
    > says...
    >
    >> Actually, considering how bad SLRs are, I would very strongly suggest
    >> you stick with your Sony R1. Obviously it doesn't have all those
    >> problems and is a much better match for you.


    > But I want more MP ;-)


    A Sony Alpha 350 has more MP, has some features you claim DSLRs don't
    have, and doesn't have some of the disadvantages you claim DSLRs
    suffer from. In other words, like the R1, it's a hybrid monster which
    depending on your point of view either falls miserably between two
    stools or navigates interestingly between the Scylla and Charybdis of
    two ossified camera technologies. It's the sort of camera I can
    imagine the R1 design team coming up after someone suggested they try
    again but this time make it a DSLR.

    What don't you like about the 350?

    --
    Chris Malcolm DoD #205
    IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
    [http://www.dai.ed.ac.uk/homes/cam/]
     
    Chris Malcolm, Jun 18, 2008
    #9
  10. Ilya Zakharevich

    nospam Guest

    In article <>, TRoss
    <> wrote:

    > DSLRs do not have a "movie mode" because, Survey Says....


    they're likely to get it
    >
    > 1. DSLRs have a mechanical shutter
    > 2. DLSRs have a reflex mirror
    > 3. DLSRs can't capture images at 24 fps


    pentax k20d can capture at 20fps. once the rest of the camera can
    handle the data rate, they'll do full video.

    > 4. DLSR sensors don't have video out


    live view.

    > 5. There is no place to put a microphone


    plenty of room

    > 6. That's what a camcorder is for


    i agree but users wants movie mode.

    > 7. Camera makers are holding back the technology to protect camcorder
    > sales


    nonsense.

    > Also, consider the lifespan of a mechanical shutter is around 100,000
    > actuations. At 24fps, you would get about 1 hour of movie footage
    > before shutters start to fail.


    the mechanical shutter stays *open*.

    > And before you go off on another tangent, consider that replacing the
    > mechanical shutter with an electronic shutter would compromise image
    > quality. I don't think anyone would find that desirable.


    for movies, nobody much cares.
     
    nospam, Jun 19, 2008
    #10
  11. Ilya Zakharevich

    nospam Guest

    In article <>, Alfred Molon
    <> wrote:

    > In article <180620081337392681%>, nospam says...
    >
    > > no, they don't. two that came up in a quick google search:
    > >
    > > 97% coverage:
    > > <http://www.steves-digicams.com/nikon880.html>
    > >
    > > 80% coverage:
    > > <http://www.dpreview.com/news/0702/07022006_nikonp5000.asp>

    >
    > All cameras I've so used so far have 100% coverage. Besides, why would a
    > manufacturer cut away the borders.


    i have no idea why. ask nikon. however, just because a camera has
    live view with an lcd and/or evf does not mean it has 100% coverage.

    > > it depends on the viewfinder screen. if dof accuracy is important,
    > > select a different screen.

    >
    > Tell me how to change the viewfinder screen on a DSLR.


    it depends on the camera. on some, it's designed to be removed, and on
    others it takes a little bit of effort.

    here's one guide:
    <http://www.earthboundlight.com/phototips/changing-nikon-focus-screens.h
    tml>

    and a video:
    <http://www.youtube.com/watch?v=3IjSPL584zg>

    it was a whole lot easier back in the film days, and with quite a
    variety of screens too:
    <http://www.mir.com.my/rb/photography/hardwares/classics/nikonf3ver2/scr
    eens/index.htm>

    custom screens for dslrs are available at:
    <http://www.katzeyeoptics.com/>
     
    nospam, Jun 19, 2008
    #11
  12. Ilya Zakharevich

    Paul Furman Guest

    Alfred Molon wrote:
    > Ray Fischer says...
    >
    >>> 2. Mirror slap vibrations: you are forced to use MLU which not all DSLRs
    >>> offer. Problem does not exist in compacts...

    >> It doesn't exist in SLRs, either.

    >
    > Then why do some DSLRs have MLU? Besides I saw some sample images,
    > with/without MLU where you could clearly see that the image taken
    > without MLU was soft.


    MLU is only an issue for rather picky shots of a particular type where
    you would want the better image of a DSLR anyways. The new live view
    DSLRs are of course in MLU mode.

    >>> 6. DOF preview being inaccurate anyway for checking DOF

    >> That one is completely false.

    >
    > Completely true. See the link I posted:
    > http://www.dphotoexpert.com/2007/09/21/live-view-versus-the-cheating-dslr-viewfinder/


    Compacts don't really show much DOF effect except with closeups. Anyways
    the advantage of having a crisp real image of the scene to evaluate is
    worth such a minor difference. With the P&S I used to come home with
    lots of images with bits of garbage and stupid things featured
    prominently that I didn't notice because they were just 3 beige pixels
    in the LCD.

    There are things about live view I like but I wouldn't trade my DSLR for
    a camera with the same sensor, mount and only live view. If it was a
    good idea someone would have made such a thing... I know there are a few
    that come close, the Sigma, Leica, etc but none have been successfully.
    It does seem it would be a simple thing to knock the mirror off a DSLR &
    keep the interchangeable lens mount but it hasn't been done. It would be
    a neat second body option.

    --
    Paul Furman
    www.edgehill.net
    www.baynatives.com

    all google groups messages filtered due to spam
     
    Paul Furman, Jun 19, 2008
    #12
  13. Ilya Zakharevich

    Ray Fischer Guest

    Alfred Molon <> wrote:
    >In article <48593a81$0$17227$>, Ray Fischer
    >says...
    >
    >> >2. Mirror slap vibrations: you are forced to use MLU which not all DSLRs
    >> >offer. Problem does not exist in compacts...

    >>
    >> It doesn't exist in SLRs, either.

    >
    >Then why do some DSLRs have MLU?


    For those rare occasions where it matters.

    >> >3. DLSR Viewfinder which could be misaligned with the main sensor
    >> >resulting in tilted images. Problem does not exist in compacts.

    >>
    >> Vastly higher resolution in the SLR's viewfinder.
    >>
    >> >4. Optical viewfinder not showing 100% of the scene (this is really
    >> >pathetic - any camera with live preview shows 100%)

    >>
    >> NO camera with live preview shows 100% of the scene. They all show
    >> very low resolution versions of the scene.

    >
    >They do. 100% means that they show the whole scene being captured,
    >without cutting away the borders.


    But with such low resolution that you canot use it for determining
    sharpness.

    >> >5. Optical viewfinder being too dark if you use DOF preview

    >>
    >> LCD screen completely unviewable in bright light.

    >
    >Then use the EVF.


    "Optical viewfinder not showing 100% of the scene"

    >> >6. DOF preview being inaccurate anyway for checking DOF

    >>
    >> That one is completely false.

    >
    >Completely true. See the link I posted:
    >http://www.dphotoexpert.com/2007/09/21/live-view-versus-the-cheating-dslr-viewfinder/


    Completely false. DOF preview shows you exactly what is coming
    through the lens. And no, I am not so gullible as to believe
    everything I see on the web.

    >> >The only solution to all these problems is to have live preview on a
    >> >high res LCD screen or EVF.

    >>
    >> When you find a camera that has a 6MP LCD screeen you let us know.

    >
    >1024x768 RGB pixel would be sufficient.


    Yeah, people really flock to those 0.8MP cameras.

    >Actually, forgot to mention in my previous post that it's a shame that
    >DLSRs have no movie mode.


    Buy a camcorder.

    --
    Ray Fischer
     
    Ray Fischer, Jun 19, 2008
    #13
  14. Ilya Zakharevich

    Paul Furman Guest

    Alfred Molon wrote:
    > In article <4859ebe7$0$17189$>, Ray Fischer
    > says...
    >
    >>> Completely true. See the link I posted:
    >>> http://www.dphotoexpert.com/2007/09/21/live-view-versus-the-cheating-dslr-viewfinder/

    >> Completely false. DOF preview shows you exactly what is coming
    >> through the lens. And no, I am not so gullible as to believe
    >> everything I see on the web.

    >
    > Sure. And those sample images of the chessboard are fakes, right?


    It's real, 85mm f/1.2 at close focus is extreme though. At f/2.8 it's a
    minor difference if even perceptible.

    >>>>> The only solution to all these problems is to have live preview on a
    >>>>> high res LCD screen or EVF.
    >>>> When you find a camera that has a 6MP LCD screeen you let us know.
    >>> 1024x768 RGB pixel would be sufficient.

    >> Yeah, people really flock to those 0.8MP cameras.

    >
    > You can easily zoom into the image on the LCD, even down to pixel level.
    > You don't need to see the entire image at pixel level to focus, a small
    > part of the image is sufficient.


    If you want to work faster or more freely it helps a lot to have the big
    picture clear. Even with an f/1.2 lens, it gives a good idea where the
    plane of sharpest focus is and with a super fast lens like that, yes,
    you just have to imagine a shallower DOF till you see the shot a moment
    later. For slow studio work that delay isn't a big deal, for on the fly
    shooting you have 'enough' control for most situations.

    One case where live view would be nice is when working with a super-fast
    lens like that going for the hollywood bokeh circles, then you can
    really compose those circles. Or just for setting up in a particular
    situation: it is cool to be able to be able to see the real size of
    those OOF circles & see exactly how much is in focus and then once
    you've got the right settings, you can go ahead & shoot away.

    Anyways if you are working at 85mm f/1.2 you *are* using a Canon DSLR,
    (or a film camera: that's equivalent to 135mm f/2) or a Nikon 58mm f/1.2
    or some other high end solution which is not a P&S fixed lens EVF camera.

    --
    Paul Furman
    www.edgehill.net
    www.baynatives.com

    all google groups messages filtered due to spam
     
    Paul Furman, Jun 19, 2008
    #14
  15. Alfred Molon <> wrote:
    > In article <>, Chris Malcolm says...


    >> A Sony Alpha 350 has more MP, has some features you claim DSLRs don't
    >> have, and doesn't have some of the disadvantages you claim DSLRs
    >> suffer from. In other words, like the R1, it's a hybrid monster which
    >> depending on your point of view either falls miserably between two
    >> stools or navigates interestingly between the Scylla and Charybdis of
    >> two ossified camera technologies. It's the sort of camera I can
    >> imagine the R1 design team coming up after someone suggested they try
    >> again but this time make it a DSLR.
    >>
    >> What don't you like about the 350?


    > I actually ordered the 350 yesterday, only to have my order cancelled 15
    > minutes later because they could not deliver.


    I was lucky enough to have ordered the last one of a package deal of
    the 350 with the Sony version of the 18-250 "surprisingly good" Tamron
    zoom. I notice that more of that particular package deal are springing up.

    > The 350 is tempting, but it not so suitable for high ISO (800 and
    > above). Another thing, the live view is not a direct video feed from the
    > main sensor, so there could be misalignments and you can't zoom in down
    > to pixel level. It also does not show 100% of the image you capture.
    > Nethertheless it's an excellent live view implementation, as phase
    > detection AF is enabled all the time.


    > The other candidate is the Pentax K20D or its twin the Samsung GX-20.
    > Much better body and OVF, and the live view shows 100% and can zoom down
    > to pixel level. But the live view is a bit crippled because there is no
    > histogram and you can't change the exposure parameters in live view.


    > In any case it will be one of these to cameras (the 350 or the
    > K20/GX20).


    Keep on eye on this Flickr set, where I'll be putting up some
    evaluative photographs taken by this combination. Gusty winds and
    rain-threatening clouds don't promise much for this afternoon :-(

    http://www.flickr.com/photos/chris_malcolm/sets/72157605701184485/

    --
    Chris Malcolm DoD #205
    IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
    [http://www.dai.ed.ac.uk/homes/cam/]
     
    Chris Malcolm, Jun 19, 2008
    #15
  16. ? "TRoss" <> ?????? ??? ??????
    news:...
    > On Wed, 18 Jun 2008 22:23:05 +0200, Alfred Molon
    > <> wrote:
    >
    >>In article <>, TRoss says...
    >>> Repeat after me ... DSLRs do not have an EVF.
    >>>
    >>> If the camera has an EVF, it isn't a DSLR. A camera that has an EVF
    >>> has no need for a reflex mirror, which is one defining characteristic
    >>> of an SLR camera. The other defining characteristic is a single lens.
    >>>
    >>> Besides, an EVF would pretty much be worthless for checking DOF. The
    >>> size is too small and the resolution is too low.

    >>
    >>How about a high resolution EVF. Besides, OVFs are the same size as
    >>EVFs. If an EVF is too small for checking DOF, an OVF is also
    >>
    >>
    >>> If the DOF preview isn't 100% accurate, and I'm not saying it isn't,
    >>> it is close enough to be a useful tool. The DOF markers on some lenses
    >>> are useful tools, too.

    >>
    >>Well, if you look at the images of the chessboard on that page you'll
    >>see that the difference in DOF between what appears in the OVF and the
    >>final image is huge.

    >
    > Fine. You're convinced it isn't accurate and that inaccuracy is a big
    > problem and a deficiency. I think it is accurate, or at least accurate
    > enough to be useful.
    >
    >>> >1024x768 RGB pixel would be sufficient.
    >>>
    >>> For composing, sure. It wouldn't be sufficient for manual focusing.

    >>
    >>It would, because you can zoom into it, even down to pixel level if
    >>necessary. Actually I'm quite sure a zoomable 640x480 LCD would suffice
    >>to precisely set manual focus and DOF.
    >>
    >>> And it would be pretty much worthless in bright light.

    >>
    >>I've been using camera LCDs in any lighting condition on a variety of
    >>cameras and can tell you that LCDs are very usable even in bright light.
    >>
    >>> DSLRs do not have a "movie mode" because, Survey Says....
    >>>
    >>> 1. DSLRs have a mechanical shutter
    >>> 2. DLSRs have a reflex mirror
    >>> 3. DLSRs can't capture images at 24 fps
    >>> 4. DLSR sensors don't have video out
    >>> 5. There is no place to put a microphone
    >>> 6. That's what a camcorder is for
    >>> 7. Camera makers are holding back the technology to protect camcorder
    >>> sales

    >>
    >>It seems that you missed all the advances in camera technology of the
    >>last few years.

    >
    > And you seem to be obsessing about a couple of characteristics of
    > DSLRs you find objectionable.
    >
    >>There are now several DLSRs with sensors capable of life
    >>view - just lift that mirror up. There are even things called
    >>"electronic shutters".

    >
    > I don't see electronic shutters replacing curtain shutters in DSLRs
    > any time soon. If at all. The biggest reason is shutter lag. Smear and
    > bloom are two other problems that would have to be addressed.
    >
    >
    >>Your objection Nr. 5 "There is no place to put a microphone" is
    >>incredible. No space for a microphone on a huge DLSR, but enough space
    >>on a tiny compact?
    >>
    >>> Also, consider the lifespan of a mechanical shutter is around 100,000
    >>> actuations. At 24fps, you would get about 1 hour of movie footage
    >>> before shutters start to fail.
    >>>
    >>> And before you go off on another tangent, consider that replacing the
    >>> mechanical shutter with an electronic shutter would compromise image
    >>> quality. I don't think anyone would find that desirable.

    >>
    >>Apparently the Pentax K20D has a mechanical shutter and an electronic
    >>shutter. With the electronic shutter the K20D is capable of capturing 20
    >>images at 1.5MP per second.

    >
    > In a 6-second burst. And if I'm not mistaken, the K20D is a 14.6MP
    > camera. I think reducing it to a 1.5MP camera qualifies as
    > compromising image quality.
    >
    >
    > Maybe one day a DSLR will be able to capture live action video. And
    > maybe one day a camcorder will be able to produce still images that
    > rival the quality of a DSLR.
    >

    That would seriously compromise either. My camcorder has an 800 kpixel
    sensor, which is fine for video, but it's only crappy 640 X 480 stills. My
    still camera leaves a lot to be desired on its video capability. And that's
    what it should be.


    --
    Tzortzakakis Dimitrios
    major in electrical engineering
    mechanized infantry reservist
    hordad AT otenet DOT gr
     
    Tzortzakakis Dimitrios, Jun 19, 2008
    #16
  17. Alfred Molon <> wrote:
    > In article <>, Chris Malcolm says...


    >> Keep on eye on this Flickr set, where I'll be putting up some
    >> evaluative photographs taken by this combination. Gusty winds and
    >> rain-threatening clouds don't promise much for this afternoon :-(
    >>
    >> http://www.flickr.com/photos/chris_malcolm/sets/72157605701184485/


    > The rose image looks good. I wonder how it would look with some
    > additional sharpening.


    The rose was shot from a tripod.

    > The experimental upsample is soft. I downloaded it and resized it to 50%
    > (back to the original size), applued some unsharp mask and it still
    > didn't look crisp and sharp. Did you shoot RAW?


    That one was hand held in a rather blustery wind. I'll start shooting RAW
    once I've discovered how far the in-camera jpegs can go.

    --
    Chris Malcolm DoD #205
    IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
    [http://www.dai.ed.ac.uk/homes/cam/]
     
    Chris Malcolm, Jun 20, 2008
    #17
  18. Ilya Zakharevich

    Ray Fischer Guest

    Alfred Molon <> wrote:
    > Ray Fischer


    >> >Completely true. See the link I posted:
    >> >http://www.dphotoexpert.com/2007/09/21/live-view-versus-the-cheating-dslr-viewfinder/

    >>
    >> Completely false. DOF preview shows you exactly what is coming
    >> through the lens. And no, I am not so gullible as to believe
    >> everything I see on the web.

    >
    >Sure. And those sample images of the chessboard are fakes, right?


    Explain to us how the image seen through the viewfinder of a dSLR can
    be different from the image recorded by the sensor given that the
    image is produced by exactly the same lens under exactly the same
    conditions.

    Perhaps your source doesn't realize that there is a DOF button that
    lets one stop down the lens. Perhaps he's incompetant. Perhaps it's
    just a mistake.

    But I don't blindly believe things that make no sense without even a
    hint of an explanation. You shouldn't either.

    --
    Ray Fischer
     
    Ray Fischer, Jun 20, 2008
    #18
  19. Ray Fischer wrote:
    []
    > Explain to us how the image seen through the viewfinder of a dSLR can
    > be different from the image recorded by the sensor given that the
    > image is produced by exactly the same lens under exactly the same
    > conditions.
    >
    > Perhaps your source doesn't realize that there is a DOF button that
    > lets one stop down the lens. Perhaps he's incompetant. Perhaps it's
    > just a mistake.
    >
    > But I don't blindly believe things that make no sense without even a
    > hint of an explanation. You shouldn't either.


    The explanation was, that the sensor accepts a ray bundle with a larger
    angle than the viewfinder (if I understood the earlier commentary
    correctly). In other words, once the lens opening gets wider than f/2.8
    (or whatever), the viewfinder will show no smaller depth-of-field. On
    that particular camera. If you changed the viewfinder things could be
    different.

    I can't comment if that's right in practice (as I no longer have such
    large aperture lenses).

    David
     
    David J Taylor, Jun 20, 2008
    #19
  20. Ilya Zakharevich

    Paul Furman Guest

    David J Taylor wrote:
    > Ray Fischer wrote:
    > []
    >> Explain to us how the image seen through the viewfinder of a dSLR can
    >> be different from the image recorded by the sensor given that the
    >> image is produced by exactly the same lens under exactly the same
    >> conditions.
    >>
    >> Perhaps your source doesn't realize that there is a DOF button that
    >> lets one stop down the lens. Perhaps he's incompetant. Perhaps it's
    >> just a mistake.
    >>
    >> But I don't blindly believe things that make no sense without even a
    >> hint of an explanation. You shouldn't either.

    >
    > The explanation was, that the sensor accepts a ray bundle with a larger
    > angle than the viewfinder (if I understood the earlier commentary
    > correctly). In other words, once the lens opening gets wider than f/2.8
    > (or whatever), the viewfinder will show no smaller depth-of-field. On
    > that particular camera. If you changed the viewfinder things could be
    > different.


    That might be part of it, the part I understand is that the screen is
    only partially translucent so some of the image comes through. It's
    awkward to explain... if instead of a ground 'glass' focusing screen, if
    you had an opaque white projection surface and looked at that from the
    other side, that should look correct but you see that image combined
    with a clear view from your eye and your eye has a much smaller sensor
    than a DSLR (well the part used for viewing in this case anyways). Maybe
    I'm missing some terminology, the opening in your eye is much smaller
    than the 42mm opening in a DSLR so it's not capable of using the wider
    angle rays. It's like holding a video camera up to a DSLR lens, you
    won't get the shallow DOF so people invented a device that projects the
    lens image onto ground glass and the video camera focuses on the ground
    glass rather than focusing on infinity. Sorry, I know I haven't
    explained very clearly.

    > I can't comment if that's right in practice (as I no longer have such
    > large aperture lenses).



    --
    Paul Furman
    www.edgehill.net
    www.baynatives.com

    all google groups messages filtered due to spam
     
    Paul Furman, Jun 21, 2008
    #20
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